Table 2. Standard Deviation of the Calibrated Versus 
Measured Grid 
Similarity 
Affine 
S-19930 
Image A 
X 
= 
5.8 pm 
X 
= 
3.5 
pm 
y 
= 
4.8 
y 
= 
1.6 
R 
= 
7.5 
R 
= 
3.8 
Image C 
X 
= 
6.7 pm 
X 
= 
4.4 
pm 
y 
= 
5.3 
y 
= 
1.4 
R 
= 
8.5 
R 
= 
4.6 
S-19931 
Image B 
X 
= 
5.4 pm 
X 
= 
3.8 
pm 
y 
= 
4.3 
y 
= 
1.6 
R 
= 
6.9 
R 
= 
4.2 
Image D 
X 
= 
6.3 pm 
X 
= 
4.8 
pm 
y 
= 
4.6 
y 
= 
2.1 
R 
= 
7.8 
R 
= 
5.2 
Values are given at tube scale 
1 pm at vidicon tube = 3.9 meters at ground 
Table 3. Standard Deviation of the Nominal Versus 
Measured Grid 
Similarity 
Affine 
S-19930 
Image A 
X 
_ 
5.6 pm 
X 
_ 
5.0 
pm 
y 
= 
3.4 
y 
= 
2.3 
R 
= 
6.6 
R 
= 
5.5 
Image C 
X 
= 
6.3 pm 
X 
= 
5.7 
p m 
y 
= 
3.5 
y 
= 
2.2 
R 
= 
7.2 
R 
= 
6.1 
S-19931 
Image B 
X 
_ 
5.9 pm 
X 
_ 
5.4 
pm 
y 
= 
3.4 
y 
= 
2.4 
R 
= 
6.8 
R 
= 
5.9 
Image D 
X 
= 
6.8 Pm 
X 
= 
6.6 
pm 
y 
= 
3.2 
y 
= 
2.4 
R 
= 
7.5 
R 
= 
7.0 
Values are given at tube scale 
1 pm at vidicon tube = 3.9 meters at ground 
Each point was measured twice and the average used as the 
best value. Image A, in addition, was measured twice by 
two different operators. To test whether the two operators 
were identifying and measuring the same points their 
measurements were adjusted one to the other by means of a